Buggy code:
public static boolean isAuthorized ( ) { } protected boolean ifAllowed ( EntityQuestionAttributes eqa ) { } @ Transactional ( readOnly = false , propagation = Propagation . REQUIRED ) protected long createQuestion ( String questionText ) { } @ Transactional ( readOnly = false , propagation = Propagation . REQUIRES_NEW ) protected EntityQuestionAttributes createAttributes ( String fileLocationLink , String metaCategory , String category1 , String category2 , int levelOfDifficulty , List < String > answers , String correctAnswerChar , int answerOptionsNumber , String description , EntityQuestion objectQuestion , EntityCompany company ) { } @ Transactional ( readOnly = false , propagation = Propagation . REQUIRED ) protected EntityAnswersText writeNewAnswer ( String answer , EntityQuestionAttributes qAttrId ) { } @ Transactional ( readOnly = false , propagation = Propagation . REQUIRED ) protected EntityAnswersText writeNewAnswer ( String answer , long keyAttr ) { } protected EntityCompany getCompany ( ) { } @ Transactional ( readOnly = false , propagation = Propagation . REQUIRES_NEW ) protected boolean fullCreateNewQuestion ( String questionText , String metaCategory , String category1 , String category2 , int levelOfDifficulty , String description , String fileLocationLink , List < String > answers , String correctAnswerChar , int answerOptionsNumber ) { } @ Override protected String getLimitsForQueryWithWhere ( ) { } @ Override @ Transactional ( readOnly = false , propagation = Propagation . REQUIRES_NEW ) public boolean CreateNewQuestion ( String questionText , String fileLocationLink , String metaCategory , String category1 , int levelOfDifficulty , List < String > answers , String correctAnswerChar , int questionNumber , int numberOfResponsesInThePicture , String description , String codeText , String category2 ) { } @ Override @ Transactional ( readOnly = false , propagation = Propagation . REQUIRES_NEW ) public boolean CreateNewQuestion ( String category1 , int levelOfDifficulty , String description ) { } @ Override @ Transactional ( readOnly = false , propagation = Propagation . REQUIRES_NEW ) public boolean CreateNewQuestion ( String category , int levelOfDifficulty , List < String > answerOptions , String correctAnswer , String description , String fileLocationLink ) { } @ Override @ Transactional ( readOnly = false , propagation = Propagation . REQUIRES_NEW ) public boolean ModuleForBuildingQuestions ( String byCategory , int diffLevel , int nQuestions ) { } @ Override public boolean ModuleForBuildingQuestions ( String byCategory , String byCategory1 , int diffLevel , int nQuestions ) { } @ Override public List < String > getAllCategories1FromDataBase ( ) { } @ Override public List < String > getAllCategories2FromDataBase ( ) { } @ Override public List < String > getAllMetaCategoriesFromDataBase ( ) { } @ Override @ Transactional ( readOnly = false , propagation = Propagation . REQUIRES_NEW ) public String deleteQuetionById ( String questionID ) { } protected void DeleteImageFromFolder ( String linkForDelete ) { } @ SuppressWarnings ( "unchecked" ) @ Override public List < String > SearchAllQuestionInDataBase ( String metaCategory , String category1 , String category2 , int levelOfDifficulty ) { } @ Transactional ( readOnly = false , propagation = Propagation . REQUIRES_NEW ) public boolean UpdateTextQuestionInDataBase ( String questionID , String questionText , String descriptionText , String codeText , String category1 , String metaCategory , String category2 , int levelOfDifficulty , List < String > answers , String correctAnswer , String fileLocationPath , String numAnswersOnPictures ) { } @ SuppressWarnings ( "unchecked" ) @ Override public List < Long > getUniqueSetQuestionsForTest ( String metaCategory , String levelsOfDifficulty , Long nQuestion ) { List < Long > result = new ArrayList < Long > ( ) ; if ( ( nQuestion > 0 ) && ( metaCategory != null ) ) { String [ ] categoryArray = metaCategory . split ( "," ) ; String [ ] levelsArray = levelsOfDifficulty . split ( "," ) ; StringBuffer condition = new StringBuffer ( ) ; EntityCompany ec = getCompany ( ) ; if ( ( categoryArray . length ) > ( MaintenanceService . MIN_NUMBER_OF_CATEGORIES ) ) { for ( int i = 0 , j = 1 ; j < ( categoryArray . length ) ; i = i + 2 , j ++ ) { condition = condition . append ( "<seq2seq4repair_space>OR<seq2seq4repair_space>((c.levelOfDifficulty=?" ) . append ( ( i + 3 ) ) . append ( ")<seq2seq4repair_space>AND<seq2seq4repair_space>(c.metaCategory=?" ) . append ( ( i + 4 ) ) . append ( ")" ) ; if ( ec != null ) condition . append ( "<seq2seq4repair_space>AND<seq2seq4repair_space>(c.companyId=?" ) . append ( ec . getId ( ) ) . append ( ")" ) ; condition . append ( ")" ) ; } } StringBuilder fullQuery = new StringBuilder ( "SELECT<seq2seq4repair_space>c.id<seq2seq4repair_space>FROM<seq2seq4repair_space>EntityQuestionAttributes<seq2seq4repair_space>c" ) ; <START_BUG> fullQuery . append ( "<seq2seq4repair_space>WHERE<seq2seq4repair_space>((c.levelOfDifficulty=?1)<seq2seq4repair_space>AND<seq2seq4repair_space>(c.metaCategory?2)" ) ; <END_BUG> if ( ec != null ) fullQuery . append ( "<seq2seq4repair_space>AND<seq2seq4repair_space>(c.companyId=?" ) . append ( ec . getId ( ) ) . append ( ")" ) ; fullQuery . append ( ")" ) . append ( condition ) ; Query query = em . createQuery ( fullQuery . toString ( ) ) ; query . setParameter ( 1 , Integer . parseInt ( levelsArray [ 0 ] ) ) ; query . setParameter ( 2 , categoryArray [ 0 ] ) ; if ( ( categoryArray . length ) > ( MaintenanceService . MIN_NUMBER_OF_CATEGORIES ) ) { for ( int i = 0 , j = 1 ; j < ( categoryArray . length ) ; i = i + 2 , j ++ ) { query . setParameter ( ( i + 3 ) , Integer . parseInt ( levelsArray [ j ] ) ) ; query . setParameter ( ( i + 4 ) , categoryArray [ j ] ) ; } } List < Long > allAttributeQuestionsId = query . getResultList ( ) ; result = MaintenanceService . randomAttributeQuestionsId ( allAttributeQuestionsId , nQuestion ) ; } return result ; } private static List < Long > randomAttributeQuestionsId ( List < Long > allAttributeQuestionsId , Long nQuestion ) { }

Fix:
fullQuery . append ( "<seq2seq4repair_space>WHERE<seq2seq4repair_space>((c.levelOfDifficulty=?1)<seq2seq4repair_space>AND<seq2seq4repair_space>(c.metaCategory=?2)" ) ;